Welcome to our forum!
Does this problem occur when you connecting to Outlook for web or Outlook client? If it is outlook client, does this problem occur when connecting to other office programs when authenticating?
And do others users encounter the same problem?
According to your description, I noticed that the user has click on yes to proceed. Can the user successfully connect to outlook client after clicking yes to continue? If yes, agree with pvanberlo, the issue may be related to the default browser.
If you are using the Internet Explorer, please go to IE> Tools> Internet Options> Advanced…, check "Disable script debugging (Internet Explorer)"and "Disable script debugging (Other)", and uncheck "Display a notification about every script error." Then do the same test to check if there're any differences.
If the above is invalid or you are using other browser, it's suggested that you could try to change the default browser to check if you can connect to Outlook normally.
Hope the above help!
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.